#include "sm2alg.h"
#include "sms4.h"

//rotate n bits to the left in a 32bit buffer
#define SM4_ROTL32(buf, n) (((buf)<<n)|((buf)>>(32-n)))

uint32_t SM4_CK[32] = {
	0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269, 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
	0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249, 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
	0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229, 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
	0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209, 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
};

uint8_t SM4_SBOX[256] ={ 
	0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
	0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
	0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
	0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
	0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
	0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
	0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
	0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
	0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
	0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
	0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
	0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
	0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
	0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
	0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
	0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
};

uint32_t SM4_FK[4] = {0xA3B1BAC6, 0x56AA3350, 0x677D9197, 0xB27022DC};


static void SMS4_key_schedule(const unsigned char *key, uint32_t *rk)
{
	uint32_t tmp, buf, K[36];
	uint32_t i;

	for (i = 0; i < 4; i++)
	{
		K[i] = SM4_FK[i] ^ ( (key[4 * i] << 24) | (key[4 * i + 1] << 16) | (key[4 * i + 2] << 8) | (key[4 * i + 3]) );
	}

	for (i = 0; i < 32; i++)
	{
		tmp = K[i + 1] ^ K[i + 2] ^ K[i + 3] ^ SM4_CK[i];

		//nonlinear operation
		buf  = (SM4_SBOX[(tmp >> 24) & 0xFF]) << 24;
		buf |= (SM4_SBOX[(tmp >> 16) & 0xFF]) << 16;
		buf |= (SM4_SBOX[(tmp >> 8)  & 0xFF]) << 8;
		buf |= (SM4_SBOX[tmp & 0xFF]);

		//linear operation
		K[i + 4] = K[i] ^ ((buf) ^ (SM4_ROTL32((buf), 13)) ^ (SM4_ROTL32((buf), 23)));

		rk[i] = K[i + 4];
	}
}


void SMS4_encrypt(const unsigned char *in, unsigned char *out, const unsigned char *key)
{
	uint32_t rk[32], X[36], tmp, buf;
	uint32_t i, j;

	SMS4_key_schedule(key, rk);

	for (j = 0; j < 4; j++)
	{
		X[j] = (in[j * 4] << 24) | (in[j * 4 + 1] << 16) | (in[j * 4 + 2] << 8) | (in[j * 4 + 3]);
	}

	for (i = 0; i < 32; i++)
	{
		tmp = X[i + 1] ^ X[i + 2] ^ X[i + 3] ^ rk[i];

		//nonlinear operation
		buf  = (SM4_SBOX[(tmp >> 24) & 0xFF]) << 24;
		buf |= (SM4_SBOX[(tmp >> 16) & 0xFF]) << 16;
		buf |= (SM4_SBOX[(tmp >> 8)  & 0xFF]) << 8;
		buf |= (SM4_SBOX[tmp & 0xFF]);

		//linear operation
		X[i + 4] = X[i] ^ (buf ^ SM4_ROTL32((buf), 2) ^ SM4_ROTL32((buf), 10) ^ SM4_ROTL32((buf), 18) ^ SM4_ROTL32((buf), 24));
	}

	for (j = 0; j < 4; j++)
	{
		out[4 * j] = (X[35 - j] >> 24) & 0xFF;
		out[4 * j + 1] = (X[35 - j] >> 16) & 0xFF;
		out[4 * j + 2] = (X[35 - j] >> 8) & 0xFF;
		out[4 * j + 3] = (X[35 - j]) & 0xFF;
	}
}


void SMS4_decrypt(const unsigned char *in, unsigned char *out, const unsigned char *key)
{
	uint32_t rk[32], X[36], tmp, buf;
	uint32_t i, j;

	SMS4_key_schedule(key, rk);

	for (j = 0; j < 4; j++)
	{
		X[j] = (in[j * 4] << 24) | (in[j * 4 + 1] << 16) | (in[j * 4 + 2] << 8) | (in[j * 4 + 3]);
	}

	for (i = 0; i < 32; i++)
	{
		tmp = X[i + 1] ^ X[i + 2] ^ X[i + 3] ^ rk[31 - i];

		//nonlinear operation
		buf  = (SM4_SBOX[(tmp >> 24) & 0xFF]) << 24;
		buf |= (SM4_SBOX[(tmp >> 16) & 0xFF]) << 16;
		buf |= (SM4_SBOX[(tmp >> 8)  & 0xFF]) << 8;
		buf |= (SM4_SBOX[tmp & 0xFF]);
		
		//linear operation
		X[i + 4] = X[i] ^ (buf ^ SM4_ROTL32((buf), 2)^ SM4_ROTL32((buf), 10) ^ SM4_ROTL32((buf), 18)^ SM4_ROTL32((buf), 24));
	}

	for (j = 0; j < 4; j++)
	{
		out[4 * j] = (X[35 - j] >> 24) & 0xFF;
		out[4 * j + 1] = (X[35 - j] >> 16) & 0xFF;
		out[4 * j + 2] = (X[35 - j] >> 8) & 0xFF;
		out[4 * j + 3] = (X[35 - j]) & 0xFF;
	}
}


void SMS4_self_test(void)
{
	long times;
	unsigned char key[16], plain[16], cipher_1[16], cipher_1000000[16], temp[16];

	hex2bytes("0123456789abcdeffedcba9876543210", 32, key);
	hex2bytes("0123456789abcdeffedcba9876543210", 32, plain);
	hex2bytes("681edf34d206965e86b3e94f536e4246", 32, cipher_1);
	hex2bytes("595298c7c6fd271f0402f804c33d3f66", 32, cipher_1000000);

	printf("%-14s: ", "key"); dump_byte(key, 16);
	printf("%-14s: ", "plain"); dump_byte(plain, 16);
	printf("%-14s: ", "cipher_1"); dump_byte(cipher_1, 16);
	printf("%-14s: ", "cipher_1000000"); dump_byte(cipher_1000000, 16);

	SMS4_encrypt(plain, temp, key);
	printf("encrypt once: "); dump_byte(temp, 16);

	if(0 != memcmp(temp, cipher_1, 16)) printf("encrypt once test error\n\n");
	else printf("encrypt once test pass\n\n");

	SMS4_decrypt(cipher_1, temp, key);
	printf("decrypt once: "); dump_byte(temp, 16);

	if(0 != memcmp(temp, plain, 16)) printf("decrypt once test error\n\n");
	else printf("decrypt once test pass\n\n");

	for(times = 0; times < 1000000; times++) SMS4_encrypt(plain, plain, key);
	printf("encrypt 1000000 times: "); dump_byte(plain, 16);

	if(0 != memcmp(plain, cipher_1000000, 16)) printf("decrypt error\n\n");
	else printf("encrypt 1000000 times test pass\n\n");
}

